2 AND 5 MARKS QUESTIONS
Q.1. In the fig. is shown the diagram of the human eye. Name the marked points.
Q.3. What is an achromatic combination of prism? Draw the course of rays through such a combination.
Q.2. The figure shows the refraction of light through an equilateral prism, incident at an angle of 30°. The ray suffers a derivation of 37°. What are the angles marked as A, e and / respectively?
Q.4. What are the factors on which the deviation produced by a prism depends ?
Q.5. What is Tyndall effect?
Q.6. State whether the following statements are correct or not. Justify your answer :
a) Short sightedness can be cured by using a concave lens.
b) Long sightedness can be cured by using a convex lens.
Q.7. Are colour blindness and presbyopia the same or different. How are they cured?
Q.8. What are rod shaped and cone shaped cells? How do they help us in seeing colour ?
Q.9. What is hypermeiropia? State the two causes. With the help of ray diagrams, show (i) the eye defect hypermetropia (ii) correction of hypermetropia by using a lens.
Q.10. Study the diagram given below and answer the questions that follow it : a) Which defect of vision is represented here? Give reason for your answer.
b) Draw ray diagram to show the correction of this defect by the use of a suitable lens.
Q.11. Why does the sky look blue on a sunny day? Explain.
Q.12. The stars appear to twinkle while planets do not. Why?
Q.13. What is dispersion of light ? Name the :
(i) component of white light that deviates the least and
(ii) the component that deviates the most while passing through a glass prism.
Q.14. A student sitting at the back of a class is not able to see what is written on the blackboard. He however, sees it clearly when sitting on the front seat at an approximate distance of 1.5 m from the blackboard. Draw ray diagrams to illustrate the image formation of the blackboard writing by eye lens when he is seated at:
(i) the back seat (ii) front seat.
Q.15. Give reasons for the following :
(i) The sun appears reddish at sunrise or sunset.
(ii The sky appears dark instead of blue to an astronaut.
Q.16. What is meant by spectrum? How can we combine the components of white light after a prism has separated them?
Q.17. What is scattering of light? The colour of sun looks different at different times of the day. Why?
Q.18. What are hypermetropia and myopia? What is their cause? How are they rectified?
Q.19. Why does dispersion of white light occur?
Q.20. What is colour blindness?
Q.21. What is meant by persistence c vision?
Q.22. List four common defects of vision that can be corrected with the use of spectacles.
Q.23. (a) What will be colour of the sky in the absence of atmosphere?
(b) Why are the traffic light signals (or danger signals) of red colour?
Q.24. (a) State two main causes of a person developing near sightedness. How can this defect be corrected? (b) What is 'astigmatism' and how is this vision defect corrected?
Q.25. (a) How does the sky appear dark from the surface of the moon?
(b) What is the cause of blue colour of the ocean?
Q.26. Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropia eye is 1 metre. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.
Q.27. Why does the sun appear reddish early in the morning?
5 MARKS QUESTIONS
Q.1. (a) What is myopia? State the two caupes of myopia. With the help of labelled ray diagrams show :
(i) the eye defect myopia.
(ii) correction of myopia using a lens.
(b) Why is Vne norma1! eye unable 'to fociis on an object placed within 10 cm from the eye?
Q.2. (a) What is dispersion of white light? What is the cause of such dispersion? Draw a diagram, to show the dispersion of white light by a glass prism.
(b) A glass prism is able to produce a spectrum when white light passes through it but a glass slab does not produce any spectrum. Explain why it is so.
Q.1. In the fig. is shown the diagram of the human eye. Name the marked points.
Q.3. What is an achromatic combination of prism? Draw the course of rays through such a combination.
Q.2. The figure shows the refraction of light through an equilateral prism, incident at an angle of 30°. The ray suffers a derivation of 37°. What are the angles marked as A, e and / respectively?
Q.4. What are the factors on which the deviation produced by a prism depends ?
Q.5. What is Tyndall effect?
Q.6. State whether the following statements are correct or not. Justify your answer :
a) Short sightedness can be cured by using a concave lens.
b) Long sightedness can be cured by using a convex lens.
Q.7. Are colour blindness and presbyopia the same or different. How are they cured?
Q.8. What are rod shaped and cone shaped cells? How do they help us in seeing colour ?
Q.9. What is hypermeiropia? State the two causes. With the help of ray diagrams, show (i) the eye defect hypermetropia (ii) correction of hypermetropia by using a lens.
Q.10. Study the diagram given below and answer the questions that follow it : a) Which defect of vision is represented here? Give reason for your answer.
b) Draw ray diagram to show the correction of this defect by the use of a suitable lens.
Q.11. Why does the sky look blue on a sunny day? Explain.
Q.12. The stars appear to twinkle while planets do not. Why?
Q.13. What is dispersion of light ? Name the :
(i) component of white light that deviates the least and
(ii) the component that deviates the most while passing through a glass prism.
Q.14. A student sitting at the back of a class is not able to see what is written on the blackboard. He however, sees it clearly when sitting on the front seat at an approximate distance of 1.5 m from the blackboard. Draw ray diagrams to illustrate the image formation of the blackboard writing by eye lens when he is seated at:
(i) the back seat (ii) front seat.
Q.15. Give reasons for the following :
(i) The sun appears reddish at sunrise or sunset.
(ii The sky appears dark instead of blue to an astronaut.
Q.16. What is meant by spectrum? How can we combine the components of white light after a prism has separated them?
Q.17. What is scattering of light? The colour of sun looks different at different times of the day. Why?
Q.18. What are hypermetropia and myopia? What is their cause? How are they rectified?
Q.19. Why does dispersion of white light occur?
Q.20. What is colour blindness?
Q.21. What is meant by persistence c vision?
Q.22. List four common defects of vision that can be corrected with the use of spectacles.
Q.23. (a) What will be colour of the sky in the absence of atmosphere?
(b) Why are the traffic light signals (or danger signals) of red colour?
Q.24. (a) State two main causes of a person developing near sightedness. How can this defect be corrected? (b) What is 'astigmatism' and how is this vision defect corrected?
Q.25. (a) How does the sky appear dark from the surface of the moon?
(b) What is the cause of blue colour of the ocean?
Q.26. Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropia eye is 1 metre. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.
Q.27. Why does the sun appear reddish early in the morning?
5 MARKS QUESTIONS
Q.1. (a) What is myopia? State the two caupes of myopia. With the help of labelled ray diagrams show :
(i) the eye defect myopia.
(ii) correction of myopia using a lens.
(b) Why is Vne norma1! eye unable 'to fociis on an object placed within 10 cm from the eye?
Q.2. (a) What is dispersion of white light? What is the cause of such dispersion? Draw a diagram, to show the dispersion of white light by a glass prism.
(b) A glass prism is able to produce a spectrum when white light passes through it but a glass slab does not produce any spectrum. Explain why it is so.
